The present invention relates to a network facsimile apparatus, which conducts a session control operation based on the Session Initiation Protocol (SIP), and, after the session is established, conducts an image communication processing by employing another port.
As one of communication methods for the network facsimile transmission, there has been a method called the SIP-FAX in which image data are transmitted between a transmitter and a receiver, which are coupled to each other through a network, such as the Internet, etc., in the peer-to-peer network architecture by employing the Session Initiation Protocol.
When such the SIP-FAX method, in which the facsimile communication is conducted after establishing the connection between the transmitter and the receiver, is employed, sometimes, it would be impossible to transmit image data to the receiver due to the BUSY status of the receiver. In this case, since the transmitter cannot recognize the time when the receiver resumes the READY status, the transmitter conducts such a recovery operation that the transmitter tries to transmit again the image data by automatically issuing a recall action when a predetermined time (for instance, three minutes) has elapsed since the last call.
On the other hand, with respect to the IP telephone, which employs the VoIP (Voice over Internet Protocol), Patent Document 1 (Tokkai 2005-65049, Japanese Non-Examined Patent Publication) sets forth a technology in which, when another receipt is received during a call being currently busy over the telephone, a telephone number of the other receipt is memorized, and, at the same time, a voice response reply saying “recall later” is transmitted, and then, after the current call is finalized, an automatic recall action is conducted for the sender of the other receipt.
Further, to improve the availability of the IP terminal device, which enables a bilateral vocal communication such as telephone conversation, etc., there have been proposed various kinds of technologies, including a technology which makes it possible to automatically reply a message to a sender of another receipt when the other receipt is received during a communication being currently busy over the telephone, another technology which makes it possible to record the message sent from the sender of the other receipt, etc., (for instance, set forth in Tokkai 2005-269165, Japanese Non-Examined Patent Publication).
In the bilateral vocal communication such as the IP telephone, as far as the connection with the sender of the other receipt, received during the communication being currently busy, is established as a result of the automatic recall action conducted after the current communication is finalized, it is possible to achieve a matter by talks with the partner, irrespective of either who initially gave the call to the other.
In the SIP-FAX, however, even if the automatic recall action is conducted for the sender of the other receipt, received during the communication being currently busy, after the current communication is finalized, it is impossible for the caller to make the recalled partner (the sender of the other receipt, serving as a callee) transmit the image data stored in it to the caller, since the callee merely tries to conduct the facsimile receiving operation. For this reason, conventionally, there has been no way for making the callee transmit the image data reserved in it to the caller, except the method for recalling the callee from the caller side. Accordingly, there has been a problem that it is ineffective to wait the automatic recall action to be initiated after three minutes has elapsed, since it takes much time to complete a transmission job.
Further, although it would be possible to shorten the time period for completing the transmission job by shortening the waiting time until the automatic recall action is initiated, it is not preferable that the network incurs excessive burden due to the possible increase of a number of recalling times.
Incidentally, the cause of inability of receiving the image data at the time of its receipt is not only limited to the communication being currently busy on the line, but also assumed as one of various kinds of statuses, such as a warming up status of the apparatus, etc.